1. Field of the Invention
The invention relates to a polymer material and a polymer film.
2. Prior Art
In recent years, polymer materials having high light transmittance have become used, for example, in surface protection films for glasses, ceramics, plastics or the like, antireflection films, and filter films for optical communication. For example, PMMA (polymethyl methacrylate), polystyrene, epoxy, polyimide, silicone, and polysilane materials have been studied as polymer materials. These materials are desired to be less likely to undergo a change, for example, in refractive index or coefficient of thermal expansion upon a change in temperature. For this reason, among the above polymer materials, polyimide, epoxy, and polysilane materials have drawn attention, and an improvement in polymer materials has been attempted.
Examples of attempts include the use of a linear (straight-chain) polysilane material for optical applications (Japanese Patent Laid-Open No. 222234/1994), the use of amorphous polysilane (Japanese Patent Laid-Open No. 287916/1999), and the use of linear polysilane or branched polysilane (Japanese Patent Laid-Open No. 262728/1996).
The conventional materials, however, involve the following problems.
(1) These materials undergo a significant change in refractive index upon a change in temperature. Therefore, when optical components are formed of films of these materials, the optical components undergo a significant change in characteristics, and, consequently, desired performance cannot be obtained.
(2) The transparency is lower than that of glass materials.
(3) When electrical components or optical components are soldered to a portion near the polymer film at a temperature around 200xc2x0 C., the refractive index of the polymer film is changed from the initial refractive index value and, even when the temperature is returned to the initial value, cannot be returned to the initial refractive index value.
(4) Even when an attempt is made to cause a significant change in refractive index of the polymer film through the application of ultraviolet light with quick response, a change in refractive index is discontinuous in relation with irradiation energy. This makes it difficult to cause a desired change in refractive index with high resolution by the irradiation energy of ultraviolet light.
Accordingly, it is an object of the invention to solve the above problems of the prior art and to provide highly reliable polymer material and polymer film.
According to the first feature of the invention, a polymer material comprises a branched polysilane compound and a silicone compound blended with the branched polysilane compound in a predetermined blending ratio.
In the polymer material according to the first feature of the invention, the branched polysilane compound preferably has a degree of branching of not less than 2% and not more than 50%.
In the polymer material according to the first feature of the invention, the blending ratio of the silicone compound to the polysilane compound is preferably 40 to 90% by weight.
In the polymer material according to the first feature of the invention, the polysilane compound may be a compound wherein a silicon atom is combined to silicon atoms, as well as to a hydrocarbon group, an alkoxy group, or a hydrogen atom.
In the polymer material according to the first feature of the invention, the polysilane compound may comprise a deuterated branched polysilane compound.
In the polymer material according to the first feature of the invention, the polysilane compound may comprise a partially or wholly halogenated branched polysilane compound.
In the polymer material according to the first feature of the invention, the silicone compound may be crosslinkable or comprise an alkoxy group.
In the polymer material according to the first feature of the invention, the silicone compound may comprise a deuterated silicone compound.
In the polymer material according to the first feature of the invention, the silicone compound may be a partially or wholly halogenated silicone compound.
The polymer material according to the first feature of the invention may be in the form of a solution of the above compounds dissolved in an organic solvent soluble with the compounds.
According to the second feature of the invention, a polymer film is produced by a process comprising the steps of:
either pouring the above polymer material solution into a mold in an environment not exposed to ultraviolet light, or coating the polymer material solution onto a substrate in an environment not exposed to ultraviolet light; and
heat treating the mold or the coated substrate in the temperature range of 100 to 280xc2x0 C. to cure the polymer material.
This polymer film may have an ultraviolet cut layer on its surface.
According to the first and second features of the invention, the addition of a silicone compound to a branched polysilane compound can contribute to improved transparency and thus can realize polymer materials and polymer films having high light transmittance.
According to the third feature of the invention, a polymer material comprises a branched polysilane compound and, blended with the branched polysilane compound, a predetermined amount of a silicone compound and a predetermined amount of a photoacid generator.
In the polymer material according to the third feature of the invention, the polysilane compound may be a compound wherein a silicon atom is combined to silicon atoms, as well as to a hydrocarbon group, an alkoxy group, or a hydrogen atom.
In the polymer material according to the third feature of the invention, the branched polysilane compound is preferably a polysilane compound having a degree of branching of not less than 2% and not more than 50%.
In the polymer material according to the third feature of the invention, preferably, the silicone compound is crosslinkable or comprises an alkoxy group and the blending ratio of the silicone compound to the polysilane compound is 40 to 90% by weight.
In the polymer material according to the third feature of the invention, preferably, the photoacid generator is a trichloromethyltriazine photoacid generator and the blending ratio of the trichloromethyltriazine photoacid generator to the polysilane compound is not less than 1% by weight and not more than 5.5% by weight.
In the polymer material according to the third feature of the invention, the polysilane compound may be a deuterated branched polysilane compound.
In the polymer material according to the third feature of the invention, the polysilane compound may be a partially or wholly halogenated polysilane compound.
In the polymer material according to the third feature of the invention, the silicone compound may be a deuterated silicone compound.
In the polymer material according to the third feature of the invention, the silicone compound may be a partially or wholly halogenated silicone compound.
The polymer material according to the third feature of the invention may be in the form of a solution of the compounds dissolved in an organic solvent soluble with the compounds.
According to the fourth feature of the invention, a polymer film is produced by a process comprising the steps of:
either pouring the above polymer material solution into a mold in an environment not exposed to ultraviolet light, or coating the polymer material solution onto a substrate in an environment not exposed to ultraviolet light; and
heat treating the mold or the coated substrate in the temperature range of 100 to 280xc2x0 C. to cure the polymer material.
The polymer film according to the fourth feature of the invention may be exposed to ultraviolet light to change the refractive index of the polymer film.
The polymer film according to the fourth feature of the invention may have an ultraviolet cut layer on its surface.
According to the third and fourth features of the invention, the addition of a predetermined amount of a silicone compound and a predetermined amount of a photoacid generator to a branched polysilane compound can realize substantially no change in refractive index upon a rise in baking temperature to about 250xc2x0 C. or a rise in ambient temperature to about 250xc2x0 C. during the use of the polymer material or the polymer film and, in addition, can cause a change in refractive index upon the application of ultraviolet light with high sensitivity and high resolution. The above effect improves with increasing the amount of the photoacid generator so far as the amount of the photoacid generator added is up to the upper solubility limit of the photoacid generator.
The larger the amount of the silicone compound to the branched polysilane compound added, the better the light transmittance. The addition of the silicone compound in an optimal blending ratio can improve the above effect.
The addition of a sensitizer is effective for enhancing the sensitivity of the polysilane compound to a change in refractive index upon the application of ultraviolet light. A photoreactive peroxide or photoacid generator is generally used as the sensitizer.
The photoacid generator is preferably a trichloromethyltriazine photoacid generator. Among trichloromethyltriazine photoacid generators, those, which exhibit high light transmittance in a long wavelength region and, in addition, have a maximum absorption wavelength close to the absorption wavelength of the polysilane in ultraviolet wavelength region and a high melting point, are particularly preferred from the viewpoint of improving, for example, the light transmittance of the polymer material and the polymer film, the sensitivity to a change in refractive index upon the application of ultraviolet light, and the stability of refractive index against heat.